JP2015510614A - Device, lithographic apparatus, radiation guiding method and device manufacturing method - Google Patents

Abstract

A device with extended lifetime is provided. A waveguide in the form of a continuum of material transparent to radiation passing through it, the continuum having an entrance surface and an exit surface, and an entrance surface and / or an exit surface. A cooler configured to cool. Programmable patterning device with multiple radiation emitters, configured to provide multiple radiation beams, and with fixed and movable parts, projecting multiple radiation beams to locations on the target selected based on the pattern And at least one radiation emitter is an exposure apparatus comprising a waveguide configured to output a radiation beam including unpolarized radiation and / or circularly polarized radiation. [Selection] Figure 6

Description

This application claims the benefit of US Provisional Application No. 61 / 602,491, filed February 23, 2012, which is hereby incorporated by reference in its entirety.

  The present invention relates to a device, a lithography or exposure apparatus, a radiation guiding method, and a device manufacturing method.

  A lithography or exposure apparatus is a machine that applies a desired pattern onto a substrate or part of a substrate. This apparatus is used, for example, in the manufacture of integrated circuits (ICs), flat panel displays, other devices or structures with fine features. In conventional lithography or exposure apparatus, patterning devices, also called masks or reticles, may be used to generate circuit patterns corresponding to individual layers of ICs, flat panel displays, and other devices. This pattern is transferred onto (parts of) the substrate, for example by imaging onto a radiation sensitive material (resist) layer provided on the substrate (such as a silicon wafer or glass plate).

  In some cases, the patterning device is used to generate other patterns, such as a color filter pattern or a matrix of dots, instead of a circuit pattern. Instead of a conventional mask, the patterning device may comprise a patterning array comprising an array of individually controllable elements that produce a circuit pattern or other applicable pattern. Such a “maskless” method has an advantage that a pattern can be prepared or changed quickly and at a lower cost than a method using a conventional mask.

  Thus, maskless systems include programmable patterning devices (eg, spatial light modulators, contrast devices, etc.). The programmable patterning device is programmed (eg, electronically or optically) to form a beam with a desired pattern using an array of individually controllable elements. Types of programmable patterning devices include micromirror arrays, liquid crystal display (LCD) arrays, grating light valve arrays, and self-emitting contrast devices. A programmable patterning device is an electric device configured, for example, to move a projected spot of radiation onto a target (eg, substrate) or to intermittently direct a radiation beam from a target (eg, substrate), eg, to a radiation beam absorber. It may be formed from an optical deflector. In either such configuration, the radiation beam may be continuous.

  The maskless lithography or exposure apparatus may be provided with, for example, an optical column that can form a pattern on a target portion of the substrate, for example. The optical column may be provided with a self-radiating contrast device configured to emit the beam and a projection system configured to project at least a portion of the beam onto the target portion. The apparatus may be provided with an actuator for moving the optical column or part thereof relative to the target. Thereby, the beam may be moved relative to the target. A pattern may be formed on the substrate by switching the self-radiating contrast device “on” or “off” during movement.

  According to an embodiment of the present invention, a waveguide is formed in the form of a continuum of material transparent to radiation passing through the waveguide, the continuum having an entrance surface and an exit surface, and an entrance surface. And / or a cooler configured to cool the exit surface.

  According to an embodiment of the present invention, a programmable patterning device comprising a plurality of radiation emitters and configured to provide a plurality of radiation beams, a fixed portion and a movable portion, the plurality of radiation beams based on a pattern A projection system configured to project to a position on the selected target, wherein at least one radiation emitter is configured to output a radiation beam including unpolarized radiation and / or circularly polarized radiation. A lithography or exposure apparatus comprising a waveguide is provided.

  According to an embodiment of the present invention, directing radiation through a waveguide in the form of a continuum of material transparent to radiation, the continuum having an entrance surface and an exit surface; Cooling the surface and / or the exit surface.

  According to an embodiment of the present invention, providing a plurality of radiation beams from a plurality of radiation emitters of a programmable patterning device and projecting the plurality of radiation beams to a position on a target selected based on the pattern And at least one of said radiation emitters is provided with a waveguide configured to output a radiation beam comprising unpolarized radiation and / or circularly polarized radiation.

  Several embodiments of the present invention are described below with reference to the accompanying schematic drawings, which are exemplary only. Corresponding reference characters indicate corresponding parts in the various drawings.

1 is a diagram showing a part of a lithography or exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a top view of a portion of the apparatus of FIG. 1 according to an embodiment of the present invention.

1 is a highly schematic perspective view of a portion of a lithography or exposure apparatus according to an embodiment of the present invention.

FIG. 4 is a schematic top view showing projection by the apparatus according to FIG. 3 onto a target according to an embodiment of the present invention.

It is sectional drawing which shows a part of one embodiment of this invention.

1 is a schematic diagram of a device according to an embodiment of the present invention.

1 is a schematic diagram of a device according to an embodiment of the present invention.

1 is a schematic diagram of a device according to an embodiment of the present invention.

1 is a schematic view of a part of a device according to an embodiment of the present invention.

1 is a schematic diagram of a device according to an embodiment of the present invention.

  An embodiment of the invention relates to a lithographic apparatus, which may comprise a programmable patterning device, which may for example consist of an array of self-radiating contrast devices. For further information on such lithographic apparatus, reference may be made to WO 2010/032224 and US Patent Application Publication No. 2011-0188016, US Patent Application No. 61/473636 and US Patent Application No. 61/524190, All of which are incorporated herein by reference. Embodiments of the present invention, however, may be used with any form of programmable patterning device included, for example, in the above references.

  FIG. 1 schematically shows a schematic cross-sectional side view of a part of a lithography or exposure apparatus. In this embodiment, the device has individually controllable elements that are substantially stationary in the XY plane, as described below, but this need not be the case. The apparatus 1 includes a substrate table 2 that holds a substrate, and a positioning device 3 that moves the substrate table 2 with a maximum of 6 degrees of freedom. The substrate may be a substrate coated with a resist. In some embodiments, the substrate is a wafer. In some embodiments, the substrate is a polygonal (eg, rectangular) substrate. In some embodiments, the substrate is a glass plate. In some embodiments, the substrate is a plastic substrate. In some embodiments, the substrate is a foil. In certain embodiments, the apparatus is suitable for roll to roll manufacturing.

The apparatus 1 further comprises a plurality of individually controllable self-radiating contrast devices 4 configured to emit a plurality of beams. In some embodiments, the self-radiating contrast device 4 is a radiation emitter, such as a radiation emitting diode (eg, light emitting diode (LED), organic LED (OLED), polymer LED (PLED)), fiber laser or laser diode. (For example, a solid-state laser diode). In one embodiment, each individually controllable element 4 is a blue-violet laser diode (eg, Sanyo model number DL-3146-151). Such diodes are supplied by companies such as Sanyo, Nichia, OSRAM, and Nitride. In some embodiments, the diode emits UV radiation having a wavelength of, for example, about 365 nm or about 405 nm. In certain embodiments, the diode can provide an output power selected from the range of 0.5 mW to 250 mW, and optionally an output power of at least 50 mW. In certain embodiments, the output power of device 60, which may comprise self-radiating contrast device 4, is greater than 250 mW. In one embodiment, the size of the laser diode (bare die) is selected from the range of 100 μm to 800 μm. In some embodiments, the laser diode has a light emitting region selected from the range of 0.5 μm ² to 5 μm ² . In some embodiments, the laser diode has a divergence angle selected from the range of 5 degrees to 44 degrees. In some embodiments, the diodes are configured to provide a total brightness of about 6.4 × 10 ⁸ W / (m ² · sr) or greater (eg, light emitting area, divergence angle, output power, etc.). ).

  The self-radiating contrast device 4 is disposed on the frame 5 and may extend along the Y direction and / or along the X direction. Although one frame 5 is shown, the apparatus may have a plurality of frames 5 as shown in FIG. A lens 12 is further disposed on the frame 5. The frame 5, and thus the self-radiating contrast device 4 and the lens 12 are substantially stationary in the XY plane. The frame 5, the self-radiating contrast device 4 and the lens 12 may be moved in the Z direction by an actuator 7. Alternatively or in addition, the lens 12 may be moved in the Z direction by an actuator associated with this particular lens. Optionally, each lens 12 may be provided with an actuator.

  The self-radiating contrast device 4 may be configured to emit a beam, and the projection systems 12, 14, 18 may be configured to project the beam onto a target portion of the substrate, for example. The self-radiating contrast device 4 and the projection system form an optical column. The apparatus 1 may include an actuator (for example, a motor) 11 for moving the optical column or a part thereof with respect to the substrate. A field lens 14 and an imaging lens 18 are disposed in the frame 8, and the frame 8 may be rotatable using its actuator. The combination of the field lens 14 and the imaging lens 18 forms the movable optical element 9. In use, the frame 8 rotates about its own axis 10, for example, in the direction indicated by the arrow in FIG. The frame 8 is rotated around the axis 10 using an actuator (for example, a motor) 11. Further, the frame 8 may be moved in the Z direction by the motor 7, whereby the movable optical element 9 may be displaced with respect to the substrate table 2.

  An aperture structure 13 having an aperture on the inside may be disposed above the lens 12 and between the lens 12 and the self-radiating contrast device 4. The aperture structure 13 can limit the diffractive effects of the lens 12, the associated self-radiating contrast device 4, or the adjacent lens 12 and self-radiating contrast device 4.

  The illustrated apparatus may be used by rotating the frame 8 and simultaneously moving the substrate on the substrate table 2 below the optical column. The self-radiating contrast device 4 can emit a beam through the lenses 12, 14, 18 when they are substantially aligned with each other. By moving the lenses 14, 18, for example, an image of the beam on the substrate scans a portion of the substrate. At the same time, by moving the substrate on the substrate table 2 below the optical column, the portion of the substrate 17 exposed to the image of the self-radiating contrast device 4 is also moved. Control that switches the “on” and “off” of the self-radiating contrast device 4 at high speed by a controller that controls the rotation of the optical column or a part thereof, controls the intensity of the self-radiating contrast device 4, and controls the substrate speed. (Eg, having no output when it is “off” or having an output that is below the threshold and having an output that is above the threshold when “on”), the desired pattern on the substrate An image can be formed on the resist layer.

  The control unit 500 shown in FIG. 1 controls the overall operation of the lithography or exposure apparatus, and in particular performs an optimization process described further below. The controller 500 can be embodied as a suitably programmed general purpose computer with a central processing unit and volatile and non-volatile storage means. Optionally, the controller 500 includes one or more input / output devices such as a keyboard and screen, one or more network connections, and / or one or more interfaces to various parts of the lithography or exposure apparatus. Of course, a one-to-one relationship between the controller and the lithography or exposure apparatus is not essential. In an embodiment of the present invention, one control unit can control a plurality of lithography or exposure apparatuses. In some embodiments of the invention, multiple network computers can be used to control a single lithography or exposure apparatus. The controller 500 may also be configured to control one or more associated processing devices and substrate handling devices in a lithocell or cluster of which the lithography or exposure apparatus forms part. Further, the control unit 500 can be configured to be subordinate to a lithocell or cluster monitoring control system and / or a manufacturing plant general control system.

  FIG. 2 is a schematic top view of the apparatus of FIG. 1 having a self-radiating contrast device 4. Similar to the apparatus 1 shown in FIG. 1, the lithographic apparatus 1 includes a substrate table 2 that holds a substrate 17, a positioning device 3 that moves the substrate table 2 with a maximum of 6 degrees of freedom, a self-radiating contrast device 4, and a substrate 17. And an alignment / level sensor 19 for determining whether the substrate 17 is horizontal with respect to the projection of the self-radiating contrast device 4. As shown, the substrate 17 has a rectangular shape, but circular substrates may additionally or alternatively be processed.

  The self-radiating contrast device 4 is arranged on the frame 15. The self-radiating contrast device 4 may be a radiant light emitting diode, for example a laser diode, for example a violet laser diode. As shown in FIG. 2, the self-radiating contrast devices 4 may be arranged in an array 21 extending in the XY plane.

  The array 21 may be an elongated line. In some embodiments, the array 21 may be a one-dimensional array of self-radiating contrast devices 4. In some embodiments, the array 21 may be a two-dimensional array of self-radiating contrast devices 4.

  A rotating frame 8 may be provided, which may rotate in the direction illustrated by the arrows. The rotating frame may be provided with lenses 14 and 18 (see FIG. 1) for providing an image of each self-radiating contrast device 4. This apparatus may be provided with an actuator for rotating an optical column including the frame 8 and the lenses 14 and 18 with respect to the substrate.

  FIG. 3 is a perspective view schematically showing the rotating frame 8 provided with lenses 14 and 18 in the peripheral portion. A plurality of beams, 10 beams in this embodiment, enter one of the lenses and are projected onto a target portion of, for example, the substrate 17 held by the substrate table 2. In one embodiment, the plurality of beams are arranged in a straight line. The rotatable frame can be rotated around the axis 10 by an actuator (not shown). As a result of the rotation of the rotatable frame 8, the beams are incident on a series of lenses 14, 18 (field lens 14 and imaging lens 18). Upon entering each of the series of lenses, the beam is deflected so that the beam moves along a portion of the surface of the substrate 17. Details will be described later with reference to FIG. In one embodiment, each beam is generated by a corresponding source, ie by a self-radiating contrast device, such as a laser diode (not shown in FIG. 3). In the configuration shown in FIG. 3, both of the beams are deflected and carried by a segment mirror 30 to reduce the distance between the beams. Thereby, as will be described later, a larger number of beams can be projected through the same lens to achieve the required resolution.

  When the rotatable frame rotates, the beam enters a plurality of continuous lenses. Each time a lens is irradiated with the beam, the location of the beam on the lens surface moves. Depending on where the beam is incident on the lens, the beam is projected onto the target differently (eg with different deflections). Thus, the beam (which reaches the target) will scan and move each time a subsequent lens passes. This principle will be further described with reference to FIG.

  FIG. 4 is a top view schematically showing a part of the rotatable frame 8 in a highly schematic manner. The first beam set is denoted as B1. The second beam set is denoted as B2. The third beam set is denoted as B3. Each of the beam sets is projected through a corresponding lens set 14, 18 of the rotatable frame 8. When the rotatable frame 8 rotates, the beam B1 is projected onto the substrate 17, and the region A14 is scanned by scanning movement. Similarly, the beam B2 scans the area A24, and the beam B3 scans the area A34. Simultaneously with the rotation of the rotatable frame 8 by the corresponding actuator, the substrate 17 and the substrate table are moved in the direction D. The direction D may be a direction along the X axis shown in FIG. The envelope D may be substantially perpendicular to the beam scanning direction in the regions A14, A24, and A34.

  As a result of the movement by the second actuator in direction D (eg movement of the substrate table by the corresponding substrate table motor), successive multiple beam scans are substantially relative to each other as projected by the series of lenses of the rotatable frame 8. Is projected adjacent to. This results in substantially adjacent regions A11, A12, A13, A14 for each successive scan of beam B1 (regions A11, A12, A13 were previously scanned, as shown in FIG. A14 is scanned this time). Regions A21, A22, A23, A24 occur for beam B2 (as shown in FIG. 4, regions A21, A22, A23 have been scanned previously and region A24 has been scanned this time). Regions A31, A32, A33, A34 occur for beam B3 (as shown in FIG. 4, regions A31, A32, A33 have been scanned previously and region A34 has been scanned this time). In this way, the areas A1, A2, A3 on the substrate surface may be covered by moving the substrate in direction D while rotating the rotatable frame 8.

  By projecting multiple beams through the same lens, the entire substrate can be processed in less time (assuming the rotatable frame 8 is at the same rotational speed). This is because a plurality of beams scan the substrate 17 with each lens every time the lens passes. Thereby, the displacement amount in the direction D can be increased during a plurality of consecutive scans. In other words, when a large number of beams are projected onto the substrate through the same lens, the rotational speed of the rotatable frame at a given processing time may be reduced. Thereby, the influence by high rotational speed, such as a deformation | transformation of a rotatable frame, abrasion, a vibration, a turbulent flow, can be reduced.

  In one embodiment, as shown in FIG. 4, the plurality of beams are arranged at an angle with respect to the tangent of rotation of the lenses 14, 18. In some embodiments, the plurality of beams are arranged such that each beam overlaps or each beam is adjacent to the scanning path of adjacent beams.

  A further effect of the aspect of projecting multiple beams at once with the same lens can be seen in tolerance reduction. Due to lens tolerances (positioning, optical projection, etc.), the position of successive areas A11, A12, A13, A14 (and / or areas A21, A22, A23, A24 and / or A31, A32, A33, A34) Some inaccuracy may appear in the positioning of each other. Therefore, some overlap may be required between successive regions A11, A12, A13, A14. If, for example, 10% of one beam is overlapped, if there is one beam at a time on the same lens, the processing speed will be similarly reduced by a factor of 10%. On the other hand, in a situation where 5 or more beams are projected at the same time through the same lens, the same 10% overlap (for one beam as above) is every 5 or more projection lines. If so, the total overlap would be reduced to 2% (or less), which is roughly one fifth (or more). This has the effect of significantly reducing the overall processing speed. Similarly, by projecting at least 10 beams, the total overlap can be reduced to approximately one tenth. Therefore, the influence of tolerance generated in the processing time of the substrate can be reduced by the feature that a plurality of beams are simultaneously projected by the same lens. In addition or alternatively, a larger overlap (and thus a larger tolerance width) may be allowed. This is because if a large number of beams are projected at the same time by the same lens, the influence of the overlap on the processing is small.

  An interlace technique may be used instead of or in conjunction with simultaneously projecting multiple beams through the same lens. However, this may require more strict lens alignment. Thus, at least two beams projected onto the substrate at one time through one and the same lens have a mutual interval, and the apparatus is relative to the optical column so that subsequent beam projections are made during that interval. The second actuator may be configured to operate so as to move the substrate.

  In order to reduce the distance in the direction D between consecutive beams in one group (thus increasing the resolution in the direction D, for example), the beams are arranged obliquely with respect to the direction D. Also good. Such spacing may be further reduced by providing segment mirrors 30 in the optical path, each segment reflecting a corresponding one of the multiple beams. The segments are arranged so that the interval between the beams reflected by the mirrors is narrower than the interval between the beams incident on the mirrors. Such an effect can be realized by a plurality of optical fibers. Each of the beams is incident on a corresponding one of the plurality of fibers. These fibers are arranged along the optical path so as to narrow the distance between the beams. As a result, the beam interval on the downstream side of the optical fiber is narrower than the beam interval on the upstream side of the optical fiber.

  Such an effect may also be realized using an integrated optical waveguide circuit having a plurality of inputs each receiving a corresponding one of the plurality of beams. The integrated optical waveguide circuit is configured such that the distance between the beams on the downstream side of the integrated optical waveguide circuit is narrower than the distance between the beams on the upstream side of the integrated optical waveguide circuit along the optical path. .

  A system for controlling the focus of the image projected onto the substrate may be provided. In certain configurations described above, a configuration may be provided for adjusting the focus of an image projected by a portion or all of an optical column.

  In certain embodiments, the projection system projects at least one beam of radiation onto the substrate. The substrate is formed from a material layer on the substrate 17 on which the device is to be formed in order to cause local deposition of droplets of material (eg metal) by laser induced material transfer.

  Referring to FIG. 5, the physical mechanism of laser induced mass transfer is represented. In certain embodiments, the radiation beam 200 is focused through a substantially transparent material 202 (eg, glass) with an intensity below the plasma breakdown of the material 202. Surface heat absorption occurs on a substrate formed from a donor material layer 204 (eg, a metal film) overlying material 202. Heat absorption causes the donor material layer 204 to melt. Furthermore, the heat creates a forward induced pressure gradient that results in forward acceleration of the donor material droplet 206 from the donor material layer 204, and thus from the donor structure (eg, plate) 208. By directing the beam 200 to the appropriate location on the donor plate 208, a donor material pattern can be deposited on the substrate 17. In some embodiments, the beam is focused on the donor material layer 204.

  In certain embodiments, one or more short pulses are used to cause movement of the donor material. In certain embodiments, the pulses may be several picoseconds or femtoseconds long to obtain pseudo one-dimensional forward heat and mass transfer of the molten material. Such short pulses promote little or no lateral heat flow in the material layer 204, and thus little or no heat addition to the donor structure 208. Short pulses allow for rapid melting and forward acceleration of the material (eg, evaporating materials such as metals will lose their forward direction and result in scattered deposits). With short pulses, the heating of the material can be slightly above the heating temperature but below the evaporation temperature. For example, for aluminum, about 900 to 1000 degrees Celsius is desirable.

  In some embodiments, the use of laser pulses moves the amount of material (eg, metal) from the donor structure 208 to the substrate 17 in the form of 100-1000 nm droplets. In certain embodiments, the donor material essentially comprises or consists of a metal. In certain embodiments, the material is aluminum. In some embodiments, the material layer 204 is film-like. In certain embodiments, the film is attached to another object or layer. As mentioned above, the object or layer may be glass.

  FIG. 1 illustrates an embodiment of the present invention. The lithography or exposure apparatus 1 includes a projection system 50 including a fixed part and a movable part. The projection system may comprise lenses 12, 14, and 18, for example as shown in FIG. Projection system 50 is configured to project a plurality of radiation beams onto a target (eg, on substrate 17). This position is selected based on the pattern. The pattern is to be formed on the substrate 17. In some embodiments, the pattern is formed in a layer of photoresist material. In certain embodiments, a pattern is formed in the donor material layer, which then forms a pattern corresponding to the layer of the device.

  As shown in FIG. 6, in one embodiment, the self-radiating contrast device 4 comprises a device 60 that comprises a waveguide 61. In some embodiments, the waveguide 61 comprises an optical fiber. The lifetime of other waveguides formed from optical fibers and a continuous body of material is limited. A reduction in coupling efficiency has been observed at the end faces (ie, the entrance and / or exit faces) of optical fibers or other waveguides. It has been observed that the waveguide functions with good and stable coupling efficiency for a limited period of time, after which the output of the waveguide follows a substantially linear drop. The coupling efficiency of a waveguide is related to the ratio of radiation transmitted into and transmitted from the waveguide.

  One way to extend the lifetime of an optical fiber is to provide end caps at one or both ends of the optical fiber. A disadvantage of known optical fiber end caps is that, for approximately 10% of the optical fibers, the optical fibers degrade rapidly, which is undesirable even if end caps are used. Furthermore, it is difficult to attach the end cap. This is because 100% adhesion between the end cap and the fiber is required. If the adhesion is less than 100%, this leads to the deterioration as described above.

  It would be desirable to extend the lifetime of a device comprising a waveguide formed from a continuum of materials. In the apparatus 1 described above, there may be approximately about 10,000 devices each including a waveguide used in the apparatus. Therefore, it is particularly desirable to extend the lifetime of such devices by a percentage greater than 90% in a reliable manner.

  FIG. 6 schematically illustrates a device 60 according to an embodiment of the present invention. In certain embodiments, the device 60 comprises a waveguide 61 formed from a continuum of material. The continuum of material is transparent to the radiation passing through the waveguide 61. This continuum has an entrance surface 62 and an exit surface 63. In some embodiments, the waveguide is an optical waveguide, such as an optical fiber. In some embodiments, the optical fiber is a single mode optical fiber. In some embodiments, the optical fiber is a polarization maintaining optical fiber.

  In some embodiments, the waveguide 61 has an elongated shape. The waveguide 61 may have a longitudinal direction corresponding to the axis of the waveguide 61. However, this is not always necessary. For example, in some embodiments, the waveguide has a planar shape. In this case, the waveguide 61 receives the radiation through an arbitrary end of the planar waveguide and outputs the radiation. In some embodiments, the waveguide 61 is not hollow. The waveguide 61 is substantially packed. When the waveguide 61 has an elongated shape, the entrance surface 62 and the exit surface 63 of the waveguide 61 are located at the longitudinal ends of the waveguide 61.

  In certain embodiments, device 60 includes a cooler 70. The cooler 70 is configured to cool the entrance surface 62 and / or the exit surface 63.

  When the device 60 is in use, radiation received at the entrance surface 62 heats the entrance surface 62. By providing the cooler 70 in the device 60, the temperature of the entrance surface 62 and / or the exit surface 63 is reduced compared to a device that does not have such a cooler.

  Cooling the entrance surface 62 and / or the exit surface 63 has the effect of extending the lifetime of the device 60. This is because the decrease in the coupling efficiency of the waveguide is caused by the deformation of the end face of the waveguide. The end face deformation is caused at least in part by heat from radiation. Radiation partially melts or softens the end face, which becomes a deformation.

  In the art, it was previously thought that the reduction in the coupling efficiency of the waveguide was due to the accumulation of contaminants at the end face of the waveguide. Therefore, this discovery is a departure from the conventional idea. By using an electron microscope, it was observed that the black spot on the end face of the road was not caused by contamination but actually caused by a deformed surface. This type of surface deformation may be referred to as laser induced periodic surface structures. This type of deformation can occur in optical fibers even in particle deprived environments, where there is no possibility of significant contamination of the optical fiber end face.

  By reducing the temperature of the entrance surface 62 and / or the exit surface 63, the occurrence of a periodic surface structure on the entrance surface 62 and / or the exit surface 63 is at least slowed and possibly prevented.

  In some embodiments, the cooler 70 includes a liquid 71 that cools the entrance surface 62 and / or the exit surface 63. One end surface or both end surfaces of the waveguide 61 may be immersed in the liquid 71. The heat moves from the entrance surface 62 and / or the exit surface 63 to the liquid 71.

  The liquid 71 provides a simple way to cool the entrance surface 62 and / or the exit surface 63. However, other types of coolers 70 may be used as long as they are configured to cool the entrance surface 62 and / or the exit surface 63. In some embodiments, the liquid 71 is not in contact with the side surface of the waveguide 61.

In some embodiments, the liquid 71 is transparent to radiation that passes through the waveguide 61. By providing a liquid 71 that is transparent to the radiation, no extra mechanism is required to allow the waveguide 61 to receive and / or output the radiation while avoiding the liquid 71.
Therefore, the device 60 can have a simple structure.

  The liquid 71 need not be completely transparent to radiation. The liquid 71 desirably has at least a high level of transparency with respect to the wavelength of radiation guided by the waveguide 61. A transparency of at least 80% and optionally at least 90% is desirable.

  In some embodiments, the liquid 71 consists of water. Water is readily available, inexpensive and non-corrosive. By using water as the liquid 71 of the cooler 70, the device 60 can be manufactured inexpensively and safely. However, other types of liquid 71 may be suitably used in the cooler 70. The type of the liquid 71 is not particularly limited. For example, the liquid 71 may be ethanol. The liquid 71 may be any liquid having a high transmittance with respect to radiation having a wavelength of 405 nm.

  In some embodiments, the liquid 71 has a refractive index that is between the refractive index of the waveguide 61 and the refractive index of the medium from which the device 60 emits radiation. In certain embodiments, device 60 is configured to emit radiation into the air, for example. In some embodiments, the refractive index of the liquid 71 is greater than one.

  In some embodiments, the liquid 71 has a refractive index that is less than the refractive index of the material from which the waveguide 61 is formed. For example, the waveguide 61 may be formed from a glass material having a refractive index near about 1.5. In certain embodiments, the liquid has a refractive index in the range of about 1 to about 1.5, more desirably in the range of about 1.2 to about 1.4. In some embodiments, the liquid 71 has the same refractive index as the refractive index of the material from which the waveguide 61 is formed. This advantage is to reduce optical effects from surface deformation. In some embodiments, the liquid 71 has a refractive index that is greater than the refractive index of the material from which the waveguide 61 is formed.

  In some embodiments, the liquid 71 reduces the refractive index step between the waveguide 61 and the external environment. Liquid 71 provides an intermediate refractive index step. Thereby, the coupling efficiency of the waveguide 61 with respect to an external medium (for example, air or vacuum) is improved. In addition, the intermediate refractive index step provided by the liquid 71 can reduce distortion of the wavefront output from the waveguide 61. The liquid 71 reduces the adverse effects of the periodic surface structure that may be formed on the end face of the waveguide 61. Furthermore, this index matching by the liquid 71 has a beneficial effect on non-uniform energy application at the entrance surface 62 and / or exit surface 63 of the waveguide 61 resulting in an undesirable surface structure. Refractive index matching reduces heating at the entrance surface 62 and / or the exit surface 63 of the waveguide 61. In some embodiments, a refractive index coating is provided on the side of the waveguide 61.

  In some embodiments, the cooler 70 includes a cap 72. The cap 72 is configured to hold the liquid 71 at the entrance surface 62 and / or the exit surface 63. The waveguide 61 receives and / or outputs radiation via the liquid 71. The cap 72 is formed from a material that does not allow the liquid 71 to pass through. Liquid 71 is contained in cap 72.

  By providing the cap 72, the cooler 70 can have a simple structure for cooling the entrance surface 62 and / or the exit surface 63 of the waveguide 61. The volume capacity of the cap 72 is not particularly limited. In certain embodiments, the volume capacity of the cap is at least 50 ml and optionally at least 100 ml. In certain embodiments, the volume capacity of cap 72 is in the range of about 1 ml. In some embodiments, the cooler 70 is shared by the plurality of waveguides 61. For example, in some embodiments, each of the plurality of optical fibers has an end face within the same cap 72. The cap 72 may have a volume of about 1 ml to about 10 ml. Heat from the entrance surface 62 and / or the exit surface 63 is absorbed by the liquid 71 in the cap 72. The larger the volume of the liquid 71, the lower the average temperature rise of the liquid 71 due to the absorption of radiation. This serves to cool the entrance surface 62 and / or the exit surface 63 of the waveguide 61.

  Cap 72 has a port 73 configured to receive waveguide 61. In certain embodiments, the port 73 comprises a seal configured to form a liquid tight seal between the cap 72 and the waveguide 61. This seal at least reduces liquid loss from the cap 72 around the outer surface of the waveguide 61.

  The shape of the cap 72 is not particularly limited. In certain embodiments, the cap 72 has an elongated shape. In certain embodiments, the average diameter of the cap 72 is greater than the average diameter of the waveguide 61. In some embodiments, the cap 72 has a longitudinal direction. In some embodiments, the longitudinal direction of the cap 72 is the same as the longitudinal direction of the waveguide 61.

  In certain embodiments, the cap 72 includes a window 74. The waveguide 61 receives and / or outputs radiation via the liquid 71 and the window 74. The window 74 is formed from a material that is substantially transparent to the radiation guided by the waveguide 61. The window 74 does not pass the liquid 71.

  By providing the window 74, the remaining material of the material forming the cap 72 that holds the liquid 71 can have any optical properties. This relaxes the requirement of the cap 72. For example, the remaining portion of the cap 72 except for the window 74 can be opaque to the radiation guided by the waveguide 61. However, the cap 72 does not necessarily require the window 74. For example, the cap 72 may be formed from a material that is transparent to the radiation guided by the waveguide 61. In this case, no additional windows are required. Further, in some embodiments, the window 74 of the cap 72 is configured to shape the radiation beam output from the device 60. In some embodiments, the window 74 of the cap 72 is configured to perform a pinhole or lens function.

  As shown in FIG. 6, the cooler 70 may be configured to cool the emission surface 63 of the waveguide 61. FIG. 7 schematically illustrates a device 60 according to an embodiment of the invention. In this embodiment, the cooler 70 is configured to cool the entrance surface 62 of the waveguide 61.

  FIG. 8 shows an embodiment in which the device 60 comprises two coolers 70. One of the coolers is configured to cool the entrance surface 62. Another cooler 70 is configured to cool the exit surface 63.

  In certain embodiments, the radiation emitter comprises a device 60 according to an embodiment of the present invention. In certain embodiments, the fiber laser comprises a device 60 according to an embodiment of the present invention. For example, one or more self-radiating contrast devices 4 may comprise a fiber laser comprising a device 60 according to an embodiment of the invention.

  As shown in FIG. 6, in some embodiments, the device 60 comprises a radiation source 65. The radiation source 65 is configured to supply radiation to the waveguide 61. For example, the radiation source 65 may comprise a laser diode or other fiber laser. The laser diode may be a semiconductor laser diode. In certain embodiments, device 60 comprises a portion of a fiber laser that is pumped by a radiation source.

  In certain embodiments, radiation source 65 is configured to provide unpolarized radiation and / or circularly polarized radiation to waveguide 61. In some embodiments, the radiation source 65 is configured to provide fully unpolarized radiation to the waveguide 61. In certain embodiments, the radiation source 65 is configured to provide fully circularly polarized radiation to the waveguide 61. In some embodiments, the radiation source 65 is configured to provide a mixture of unpolarized and circularly polarized radiation to the waveguide 61. In certain embodiments, the radiation source 65 is configured to provide radiation that includes up to 10%, 5%, or 1% linearly polarized radiation. However, this is not always necessary. For example, in some embodiments, the radiation source 65 of the device 60 is configured to provide at least some, and optionally complete, linearly polarized radiation to the waveguide 61. Device 60 may be used with any polarization of radiation. The effect of the cooler 70 can reduce the occurrence of undesirable surface structures, so that linearly polarized radiation can be used without reducing the lifetime of the device 60.

  In certain embodiments, device 60 is configured to have an output of at least 50 mW. In certain embodiments, the device is configured to have an output power of at most 250 mW. In certain embodiments, device 60 is configured to induce radiation having a wavelength of about 405 nm. However, the wavelength of the radiation guided by the waveguide 61 is not particularly limited. Device 60 may comprise, for example, a blue laser, a blue-violet laser, or a portion of a violet laser. However, other emission wavelengths can be used. This is because radiation of any wavelength may have an effect of heating the entrance surface 62 and / or the exit surface 63 of the waveguide 61, which is a deformation of the entrance surface 62 and / or the exit surface 63. May cause. Thus, a device comprising a waveguide for directing radiation of any wavelength will benefit from being made according to embodiments of the present invention.

  In some embodiments, the waveguide 61 is configured to output radiation into the gas from the exit surface 63 through the cooler 70. In the context of the device 60 used in the lithography or exposure apparatus 1, the device 60 may also comprise a part of a self-radiating contrast device 4 configured to output radiation in air or optionally in vacuum. Good. The cooler 70 of the device 60 increases the coupling efficiency from the waveguide 61 to the gas or vacuum, especially after a while, the coupling efficiency of the waveguide 61 is stable in any case.

  FIG. 9 schematically illustrates a cooler 70 of a device 60 according to an embodiment of the present invention. As shown in FIG. 9, in some embodiments, the cooler 70 includes a pressurizer 80. The pressurizer 80 is configured to hold the liquid 71 under pressure. In use, the liquid 71 is pressurized by the pressurizer 80.

  The advantage of holding the liquid 71 under pressure during use is that the boiling point of the liquid 71 is effectively increased. This reduces the likelihood that the liquid 71 will boil during use of the device 60. The liquid 71 absorbs heat from the entrance surface 62 and / or the exit surface 63 of the waveguide 61 during use. Since the cooling effect of the liquid 71 is reduced, it is not desirable for the liquid 71 to boil. In particular, the cooling effect of the liquid 71 is reduced when the bubbles come into contact with the surface to be cooled. In addition, the foam can function as a lens, which reduces the coupling at the end face of the waveguide 61.

  The type of the pressurizer 80 is not particularly limited. By way of example only, in some embodiments, the pressurizer 80 may include a gas pocket 81 within the cap 72 of the cooler 70. The gas pocket 81 is filled with a gas such as air. The gas pocket 81 is separated from the liquid by an at least partially flexible membrane. The pressurizer 80 further includes a compressor 82 configured to pressurize the gas in the gas pocket 81. By pressurizing the gas in the gas pocket 81, the liquid 71 in the cooler 70 can be pressurized.

  In some embodiments, the cooler 70 includes a circulation path such that the liquid 71 flows across the entrance surface 62 and / or the exit surface 63. Such a circulation path is illustrated by an arrow in FIG. The arrow represents the movement of the liquid 71 through the cooler 70. By providing a flow of liquid 71 across the entrance surface 62 and / or exit surface 63, the average temperature of the liquid 71 in contact with the entrance surface 62 and / or exit surface 63 can be maintained at a low level. As a result, the liquid 71 can continue to cool the entrance surface 62 and / or the exit surface 63. Once the liquid 71 has absorbed heat, the liquid can escape from the cap 72 of the cooler 70. The low temperature fresh liquid flows into the cap 72 and replaces the flowing liquid 71.

  In some embodiments, the cooler 70 includes a liquid supply port 75 and a liquid outlet 76. The liquid 71 flows into the cap 72 of the cooler 70 through the liquid supply port 75. Liquid 71 flows out of cap 72 of cooler 70 through liquid outlet 76.

  An advantage of providing a flow of liquid 71 through the cooler 70 is that the flow of liquid 71 helps to remove contaminants present on the entrance surface 62 and / or exit surface 63. For example, such contaminants can otherwise accumulate on the surfaces 62, 63 due to the optical tweezer effect, particularly leading to contaminants in the optical core of the optical fiber. The flow of liquid 71 reduces the deposition that occurs at the beam focus. This flow (which may be perpendicular to the surface) moves the particles “trapped” due to the optical tweezer effect of the light beam before they effectively move to the surface. In addition, when contaminants are deposited on the surface, the flow of liquid 71 reduces the contaminants. Accordingly, the flow of liquid 71 helps to reduce the adverse effects of contaminants on the end face of the waveguide 61.

  In some embodiments, the cooler 70 includes a heater 77. The heater 77 is configured to heat to a temperature higher than the temperature of the entrance surface 62 and / or the exit surface 63. The purpose of the heater 77 is to vent gas from the cooler 70 liquid 71. This degassing helps to reduce bubble formation at the entrance surface 62 and / or the exit surface 63 of the waveguide 61. This increases the effectiveness of the cooler 70.

  The kind of heater 77 is not specifically limited. The heater 77 includes a heating element. In certain embodiments, the heater 77 comprises a thin film heater attached to the outer or inner surface of the cap 72 of the cooler 70. Other suitable types of heaters 77 may be used.

  In addition or alternatively, the liquid 71 in the cooler 70 may be at least partially degassed by depressurizing the liquid. For example, the liquid 71 may be degassed by depressurizing the liquid 71 prior to use of the liquid 71 in the device 60. In this case, once the device 60 is used, the pressure may be increased using the pressurizer 80 to increase the boiling point of the liquid 71, for example.

  In an embodiment, the lithography or exposure apparatus 1 comprises a device 60 according to an embodiment of the present invention. In certain embodiments, the lithographic or exposure apparatus comprises a programmable patterning device comprising a plurality of devices 60 configured to provide a plurality of radiation beams. In certain embodiments, the lithography or exposure apparatus includes a projection system 50. The projection system 50 includes a fixed part and a movable part, and is configured to project a plurality of radiation beams onto a position on a target (for example, the substrate 17) selected based on a pattern.

  In one embodiment, there is provided a lithography or exposure apparatus 1 comprising a programmable patterning device comprising a plurality of self-radiating contrast devices 4 and a projection system 50 comprising a fixed part and a movable part. In an embodiment, the at least one self-radiating contrast device 4 comprises a waveguide 61 configured to output a radiation beam comprising unpolarized radiation and / or circularly polarized radiation. The at least one self-radiating contrast device 4 comprises a waveguide 61 configured to output only unpolarized radiation and / or circularly polarized radiation. The waveguide 61 is configured not to output linearly polarized radiation.

  By using only non-polarized radiation and / or circularly polarized radiation, the lifetime of the self-radiating contrast device 4 can be extended. Deterioration and deformation of the end face of the waveguide 61 are reduced. This is because it has been observed that periodic surface structures that can occur on the waveguide 61 and / or the exit surface 63 of the waveguide 61 are formed in relation to the direction of linearly polarized light. In particular, the deformation ripple has been observed to be perpendicular to the polarization of the radiation. In other words, the ripple has a preferential direction. By using circularly polarized or non-polarized radiation, there is no linear polarization direction in which deformation ripples are formed. Thereby, the deformation of the end face is reduced.

  The experiment was carried out using an optical fiber whose end face was immersed in water. These experiments have shown that the shape of the radiation beam output by the optical fiber is substantially undistorted or dynamic and remains relatively stable. In addition, experiments have shown that the use of water immersion at the end face of the optical fiber helps to reduce the degradation of coupling efficiency between the optical fiber and the external medium over time.

  FIG. 10 shows an embodiment of a device 60 comprising a slab waveguide 91. A slab type waveguide is also called a planar waveguide. The slab waveguide 91 has an entrance surface 92 and an exit surface 93. The cooler 70 is configured to cool the entrance surface 92 and / or the exit surface 93 of the slab waveguide 91.

  In an embodiment, the slab waveguide comprises at least three layers of materials having different dielectric constants. The intermediate layer 95 is between the uppermost layer 94 and the lowermost layer 96. The dielectric constant of the intermediate layer 95 is different from the dielectric constant of the uppermost layer 94 and the dielectric constant of the lowermost layer 96. Each of the at least three layers 94, 95, 96 extends in a direction substantially parallel to their interface.

  In certain embodiments, device 60 comprises at least two waveguides. For example, as shown in FIG. 10, in one embodiment, device 60 includes a slab waveguide 91 and another waveguide 61. In some embodiments, the other waveguide 61 is an optical fiber. In some embodiments, radiation from another waveguide 61 is received at the interface by a slab waveguide 91. The interface corresponds to the entrance surface 92 of the slab waveguide and / or the exit surface 63 of another waveguide 61. In one embodiment, radiation is injected from another waveguide 61 into the intermediate layer 95 of the slab waveguide 91. In some embodiments, the entrance surface 92 of the slab waveguide 91 is in contact with the exit surface 63 of another waveguide 61. In some embodiments, the entrance surface 92 of the slab waveguide 91 is spaced from the exit surface 63 of the waveguide 61.

  The cooler 70 is selected from an incident surface 62 of another waveguide, an exit surface 63 of another waveguide, an entrance surface 92 of a slab waveguide 91, and / or an exit surface 93 of a slab waveguide 91. Configured to cool one or more surfaces. In an embodiment, each of the entrance surface 62 of the waveguide 61, the exit surface 63 of the waveguide 61, the entrance surface 92 of the slab waveguide 91, and the exit surface 93 of the slab waveguide 91 is cooled by the cooler 70. .

  The device 60 according to the embodiment of the present invention can be used in a lithography or exposure apparatus. However, device 60 has many applications besides lithography. For example, such a device 60 can be used especially in the field of bioscience using a 405 nm laser. Other application areas of device 60 include, for example, medical diagnostics, environmental monitoring, micro projectors and displays, communications and other electronic devices, and the like. Device 60 may be particularly used in applications involving high power blue lasers or violet lasers.

  According to the device manufacturing method, the display, integrated circuit or any other item may be manufactured from the substrate onto which the pattern is projected.

  Although this document describes the use of lithography or exposure apparatus in the manufacture of ICs as an example, it should be understood that the lithography or exposure apparatus described herein can be applied to other applications. Other applications include integrated optical systems, magnetic domain memory guide and detection patterns, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, and the like. For those other applications, those skilled in the art will consider that the terms "wafer" or "die" herein are considered synonymous with the more general terms "substrate" or "target portion", respectively. Will be able to understand. The substrates mentioned in this document are processed before or after exposure, for example by a track (typically a device that applies a resist layer to the substrate and develops the resist after exposure), a metrology tool, and / or an inspection tool. May be. Where applicable, the disclosure herein may be applied to these or other substrate processing apparatus. The substrate may also be processed multiple times, for example to produce a multi-layer IC, in which case the term substrate herein may also mean a substrate comprising a number of processing layers that have already been processed.

  The term “lens” refers to various optical components including refractive optical components, diffractive optical components, reflective optical components, magnetic optical components, electromagnetic optical components, electrostatic optical components, or combinations thereof, as the context allows. May be pointed to.

  The above description is illustrative and is not intended to be limiting. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.

Claims (15)

A waveguide in the form of a continuum of material transparent to radiation passing through it, the continuum having an entrance surface and an exit surface;
A cooler configured to cool the entrance surface and / or the exit surface;
A device comprising:   The device of claim 1, wherein the waveguide comprises an optical fiber.   The device according to claim 1, wherein the cooler includes a liquid that cools the entrance surface and / or the exit surface.   4. A device according to claim 3, wherein the liquid is transparent to radiation passing through the waveguide.   The device according to claim 3 or 4, wherein the liquid has a refractive index greater than 1 and smaller than the refractive index of the substance.   6. A device according to any one of claims 3 to 5, comprising a pressurizer configured to hold the liquid under pressure.   The device according to claim 3, wherein the cooler includes a circulation path through which the liquid flows across the entrance surface and / or the exit surface.   8. A device according to any preceding claim, wherein the cooler comprises a heater configured to heat to a temperature higher than the temperature of the entrance surface and / or the exit surface.   9. A device according to any preceding claim, comprising a radiation source configured to provide unpolarized radiation and / or circularly polarized radiation to the waveguide.   10. A device according to any preceding claim, configured to induce radiation having a wavelength of about 405nm.   An exposure apparatus comprising a radiation emitter comprising the device according to claim 1.   12. The exposure apparatus according to claim 11, further comprising a projection system that includes a fixed unit and a movable unit, and is configured to project a plurality of radiation beams onto a position on a target selected based on a pattern. A programmable patterning device comprising a plurality of radiation emitters and configured to provide a plurality of radiation beams;
A projection system comprising a fixed part and a movable part and configured to project the plurality of radiation beams onto a position on a target selected based on a pattern;
With
An exposure apparatus, wherein the at least one radiation emitter comprises a waveguide configured to output a radiation beam comprising unpolarized radiation and / or circularly polarized radiation. Directing radiation through a waveguide in the form of a continuum of material transparent to radiation, the continuum having an entrance surface and an exit surface;
Cooling the entrance surface and / or the exit surface;
A radiation induction method comprising: Providing a plurality of radiation beams from a plurality of radiation emitters of a programmable patterning device;
Projecting the plurality of radiation beams onto a position on a target selected based on a pattern;
With
At least one said radiation emitter comprises a waveguide configured to output a radiation beam comprising unpolarized radiation and / or circularly polarized radiation.

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